FIG. 4 is a diagram illustrating a configuration of a related cross-polar interference cancellation system.
In the related cross-polar interference cancellation system as illustrated in FIG. 4, when two routes of microwave communication lines are formed using a vertical polarization wave (V-polarization wave) and a horizontal polarization wave (H-polarization wave) orthogonal to each other between facing wireless station devices, interference between cross-polarization waves occurs in a wireless station device on the reception side under an influence of fading. In order to remove this interference between cross-polarization waves, the wireless station device on the reception side may notify the transmission side of transmission power control information according to a reception situation, and the wireless station device on the transmission side may control transmission powers of the V-polarization wave and the H-polarization wave based on this transmission power control information.
In the cross-polar interference cancellation system of FIG. 4, reception level measurement units 156 and 166 of a wireless station device 102 detect a reception power of the V-polarization wave and a reception power of the H-polarization wave, respectively. Here, the reception level measurement units 156 and 166 transfer signals to each other. Accordingly, when the reception power of any one of the V-polarization wave and the H-polarization wave is reduced, control of the transmission powers of the V-polarization wave and the H-polarization wave is performed at the same time by transmitting the transmission power control information to the facing wireless station device and controlling the transmission power control units 113 and 123 at the same time such that control of the transmission powers of both of the V-polarization wave and the H-polarization wave can be performed at the same time. Further, related technologies are disclosed in Patent documents 1 and 2.